Problem: A circle has a circumference of ${6}$. It has an arc of length $1$. What is the central angle of the arc, in degrees?
Answer: The ratio between the arc's central angle $\theta$ and $360^\circ$ is equal to the ratio between the arc length $s$ and the circle's circumference $c$. $\dfrac{{\theta}}{360^\circ} = \dfrac{{s}}{{c}}$ $\dfrac{{\theta}}{360^\circ} = {1} \div {6}$ $\dfrac{{\theta}}{360^\circ} = \dfrac{1}{6}$ ${\theta} = \dfrac{1}{6} \times 360^\circ$ ${\theta} = 60^\circ$ ${6}$ ${1}$ ${60^\circ}$